Heretofore numerous stimulation processes have been employed for increasing production of oil and gas wells by pumping various materials into the well for eliminating deposits of materials such as paraffin, and for dissolving obstructions which impede the flow of petroleum products from earth formations into which the well extends.
Steam has been injected into wells in secondary recovery processes to transfer heat from steam during condensation by conduction to oil bearing sand. An increase in reservoir temperature from 81.degree.F to 200.degree.F results in a 27 fold decrease in crude oil viscosity. This decrease in viscosity permits free flow of formerly "frozen" oil.
Steam injection processes heretofore practiced have enjoyed limited success. However, impurity of injected steam has resulted in formation of a "flue" through which steam passes directly from the injection well to the recovery well, diluting oil recovered and reducing heat transfer to the oil bearing sand.
Heretofore, non-condensable gases, dissolved in boiler feed water, collected in the oil bearing sand forming the "flue" through which steam flowed.
In fracturing processes particulate materials suspended in oil or other fluids are pumped downwardly through a well into the earth formation, fracturing the formation and mechanically holding the formation open to form passages to increase flow of petroleum products therethrough.
Acid treatments are sometimes employed for dissolving flow inhibiting materials out of a formation to enhance the flow of oil and gas into the bottom of a well hole.
Fracturing processes and acidizing processes generally require pumping large quantities of liquid at high pressure into a well to produce satisfactory results. For example, it may be necessary to inject 30,000 gallons or more of hydrochloric acid at pressures ranging from a few hundred pounds per square inch upward to for example, 20,000 pounds per square inch working pressure.
Heretofore, mechanical pumps have been employed for delivering the fluid at the required pressure. Pumping equipment heretofore devised for well stimulation processes has been extremely complicated and expensive.